Calibrating The Toxic Gas Instruments; Caution - MSA ALTAIR Pro H2S Manual De Operación

• For toxic instruments, perform a calibration if any of the following
occur:
• physical shock
• extended use in extreme temperatures
• high concentration exposure
• the instrument does not pass a bump test.
• Calibration is required at certain intervals by local
procedures.

Calibrating the Toxic Gas Instruments

Due to high reactivity of Cl
humidity and calibration tubing material can react with
the gas and cause the concentration reading to be
lower than the actual concentration. It is, therefore,
necessary to use dry tubing when calibrating or bump
checking with these gases. For best calibration, use
the shortest possible tubing to connect to the calibra-
tion cylinder for these gases.
• To enter the calibration mode, make sure you are in fresh,
uncontaminated air. See FIGURE 4-1 for more details.
1. In normal operating mode, hold the TEST button for two seconds.
• "TEST" "GAS" "?" displays.
2. Press and hold the TEST button for three seconds when the
"TEST" "GAS" "?" displays.
• "TEST" "CAL" screen displays
• After three seconds, "FAS" "?" displays asking the user if a
fresh air setup/calibration is desired.
3. Press the TEST button to enter zero calibration.
NOTE: Otherwise, the instrument will return to the normal
operating mode.
4. During zero calibration:
• the hour glass and "FAS" display
• If the instrument successfully calibrates:
• "OK" displays
• If the instrument does not successfully calibrate:
• "ERR" displays
• instrument returns to normal operating mode after five
seconds.
4-2

! CAUTION

and ClO
2
, gas, ambient
2